1
00:00:02,896 --> 00:00:05,931
For investigators
trying to solve a plane crash,
2
00:00:06,000 --> 00:00:09,000
the most important tool
can be the black box.
3
00:00:10,827 --> 00:00:12,931
It records every detail
in the cockpit...
4
00:00:14,448 --> 00:00:15,793
Look at this.
5
00:00:15,862 --> 00:00:17,413
Where's Charlie at?
6
00:00:17,482 --> 00:00:20,482
...and tells investigators
about vital conversations.
7
00:00:20,551 --> 00:00:22,275
Damn, it's starting to rain.
8
00:00:22,344 --> 00:00:25,586
Northwest 255,
runway 3 Centre,
clear for takeoff.
9
00:00:34,655 --> 00:00:38,586
But in the crash of Northwest
Airlines Flight 255...
10
00:00:38,655 --> 00:00:41,275
I've never been to an accident
of that scale.
11
00:00:41,344 --> 00:00:44,034
...it wasn't
what investigators heard
on the tape.
12
00:00:44,103 --> 00:00:46,310
- Control...
- TCI was un-set.
13
00:00:46,379 --> 00:00:49,241
It was what they didn't hear...
- Checked.
14
00:00:51,551 --> 00:00:54,586
...that would lead
to an astonishing conclusion.
15
00:01:00,620 --> 00:01:02,620
Mayday, mayday.
16
00:01:23,275 --> 00:01:24,827
Detroit, Michigan.
17
00:01:26,034 --> 00:01:27,793
August the 16th, 1987.
18
00:01:30,344 --> 00:01:33,206
It's 8:00 p.m.,
and the city is sweltering.
19
00:01:36,379 --> 00:01:38,655
Twenty-five kilometres
from downtown...
20
00:01:40,689 --> 00:01:43,034
...Detroit Metropolitan Airport
21
00:01:43,103 --> 00:01:45,896
is one of the busiest airports
in the United States.
22
00:01:51,137 --> 00:01:54,172
More than 1,100 airplanes use
its four runways each day.
23
00:01:58,931 --> 00:02:02,551
Today, one of those
is Northwest Airlines
Flight 255,
24
00:02:02,620 --> 00:02:04,448
bound for Phoenix, Arizona.
25
00:02:06,586 --> 00:02:08,241
Captain John Maus is in command.
26
00:02:09,482 --> 00:02:13,620
A Las Vegas native,
57-year-old Maus
is a veteran pilot.
27
00:02:18,241 --> 00:02:21,448
His first officer
is 35-year-old David Dodds,
28
00:02:21,517 --> 00:02:23,068
of Galena, Illinois.
29
00:02:24,689 --> 00:02:26,965
What don't you tell 'em
we're ready to go?
30
00:02:27,034 --> 00:02:30,172
Both have years of experience
on this type of aircraft.
31
00:02:31,655 --> 00:02:34,724
The MD-80 is also known
as the Super 80,
32
00:02:34,793 --> 00:02:37,379
and is the second generation
of the DC-9.
33
00:02:38,862 --> 00:02:40,620
The MD-80
was quite a bit longer,
34
00:02:40,689 --> 00:02:43,655
it had more powerful engines,
it could carry more people.
35
00:02:47,413 --> 00:02:49,275
For that reason,
it was a better money-maker
36
00:02:49,344 --> 00:02:51,896
for the airlines
than the DC-9 was.
37
00:02:57,068 --> 00:02:58,551
Look at this.
38
00:03:00,620 --> 00:03:03,586
The sky
between Detroit and Phoenix
is filled with storms.
39
00:03:06,862 --> 00:03:09,413
Several are moving quickly
towards the airport.
40
00:03:09,482 --> 00:03:11,448
There's a line here...
41
00:03:11,517 --> 00:03:13,517
For the crew,
it's been a long day.
42
00:03:13,586 --> 00:03:15,482
...about 25 miles wide.
43
00:03:15,551 --> 00:03:18,758
Well, if we get outta here
pretty quickly,
we won't have a delay.
44
00:03:18,827 --> 00:03:21,931
They've already flown
from Minneapolis, Minnesota,
45
00:03:22,000 --> 00:03:24,448
to Saginaw, Michigan,
and then Detroit.
46
00:03:25,103 --> 00:03:28,482
Phoenix is their next stop
on the way to Santa Ana,
California.
47
00:03:28,551 --> 00:03:31,275
If we wait
till after the storms here,
48
00:03:31,344 --> 00:03:33,344
there'll be delays
going over to Waterville.
49
00:03:33,413 --> 00:03:35,586
If they're delayed by weather,
50
00:03:35,655 --> 00:03:38,000
they may not make
their final destination.
51
00:03:44,551 --> 00:03:46,620
Let's get outta here
before it starts raining.
52
00:03:49,275 --> 00:03:53,241
The plane's 149 passengers
are also eager to leave.
53
00:04:01,068 --> 00:04:04,000
Paula Chican and her family
have been visiting relatives.
54
00:04:04,793 --> 00:04:06,655
They're heading home to Arizona.
55
00:04:07,413 --> 00:04:10,000
Her daughter Cecilia
is only four years old.
56
00:04:11,758 --> 00:04:15,068
- Looks like bags are all in.
- Why don't you tell 'em
we're ready to go?
57
00:04:16,448 --> 00:04:19,275
Ramp 255 at Delta 15, uh...
58
00:04:20,103 --> 00:04:23,379
Flight 255
is running half an hour late.
59
00:04:26,241 --> 00:04:29,103
Northwest 255 clear to go.
60
00:04:29,172 --> 00:04:32,206
- Okay, we're clear to push.
- Let's do the checklist.
61
00:04:34,586 --> 00:04:37,137
- Brakes.
- Set.
62
00:04:37,206 --> 00:04:39,793
Windshield heat...
63
00:04:39,862 --> 00:04:41,310
is on.
64
00:04:41,379 --> 00:04:43,896
Boost pumps. We've got six.
65
00:04:44,724 --> 00:04:47,551
Cabin-pressure controller:
Checked.
66
00:04:47,620 --> 00:04:50,310
Auxiliary hydraulic pumps...
pressure:
67
00:04:50,379 --> 00:04:52,137
On and checked.
68
00:04:52,206 --> 00:04:54,586
Damn, it's starting to rain.
69
00:04:55,517 --> 00:04:58,241
To beat the storms,
they need to leave immediately.
70
00:04:58,310 --> 00:05:00,517
...beacons: They're all on.
71
00:05:00,586 --> 00:05:02,896
Before Start checklist
is complete.
72
00:05:04,689 --> 00:05:07,827
Flight 255 begins moving
from the gate to the runway.
73
00:05:07,896 --> 00:05:09,586
Northwest 255...
74
00:05:10,896 --> 00:05:12,896
But because of the weather...
75
00:05:12,965 --> 00:05:16,827
Northwest 255,
now exit at Charlie,
runway 3 Centre.
76
00:05:16,896 --> 00:05:20,344
...the ground controller
gives them a last-minute
runway change.
77
00:05:27,310 --> 00:05:31,896
Okay,
out to Charlie for 3 Centre,
Northwest 255.
78
00:05:31,965 --> 00:05:34,551
Charlie for 3 Centre, right.
79
00:05:34,620 --> 00:05:35,931
Okay.
80
00:05:38,206 --> 00:05:40,068
Ladies and gentlemen, uh,
81
00:05:40,137 --> 00:05:41,827
we're currently number one
for departure.
82
00:05:41,896 --> 00:05:43,896
We should be rolling
in a couple minutes.
83
00:05:43,965 --> 00:05:46,000
Flight attendants, be seated.
Thank you.
84
00:05:50,655 --> 00:05:52,965
Blacker than hell out there.
85
00:05:54,620 --> 00:05:56,137
Where's Charlie at?
86
00:06:00,482 --> 00:06:03,206
By the time they get
to the new runway,
87
00:06:03,275 --> 00:06:05,620
they're 45 minutes
behind schedule.
88
00:06:09,586 --> 00:06:11,620
Northwest 255,
runway 3 Centre,
89
00:06:11,689 --> 00:06:13,206
clear for takeoff.
90
00:06:16,000 --> 00:06:18,206
Within 17 seconds,
91
00:06:18,275 --> 00:06:24,206
65,000 kilograms of passengers
and aircraft hurtle
down runway 3C.
92
00:06:26,724 --> 00:06:28,896
But moments before liftoff,
93
00:06:28,965 --> 00:06:32,206
Maus discovers he can't engage
the autothrottle.
94
00:06:32,275 --> 00:06:34,206
It won't stay on.
95
00:06:34,275 --> 00:06:36,137
TCI is unset.
96
00:06:37,034 --> 00:06:39,379
His computer
isn't in takeoff mode.
97
00:06:39,448 --> 00:06:41,172
They're on now.
98
00:06:41,586 --> 00:06:43,758
Okay.
99
00:06:43,827 --> 00:06:45,758
Clamp, 100 knots.
100
00:06:46,517 --> 00:06:48,793
At 313 kph...
101
00:06:48,862 --> 00:06:50,896
V1, rotate.
102
00:06:52,586 --> 00:06:55,862
...the pilots angle
the plane's nose up
for liftoff...
103
00:06:57,413 --> 00:06:59,172
...then something else
goes wrong.
104
00:07:01,241 --> 00:07:03,620
Just under 50 feet
from the ground,
105
00:07:03,689 --> 00:07:06,275
the aircraft begins rolling
from side to side.
106
00:07:10,482 --> 00:07:13,241
Tower, lifeguard copter, 120.
107
00:07:14,034 --> 00:07:16,620
It rolls left
and strikes a light pole.
108
00:07:18,275 --> 00:07:22,034
Out of control, Flight 255
slams into the ground...
109
00:07:23,655 --> 00:07:26,034
...skids along a highway...
110
00:07:27,103 --> 00:07:29,586
...and disintegrates
when it hits an overpass.
111
00:07:36,517 --> 00:07:38,620
I prayed
that everybody made it,
112
00:07:38,689 --> 00:07:41,551
but I thought
it was just a small plane
'cause it happened so quickly.
113
00:07:41,620 --> 00:07:43,793
I didn't know
it was a bigger plane.
114
00:07:43,862 --> 00:07:45,965
And... it was just awful.
115
00:07:46,034 --> 00:07:48,931
I saw the plane
come through the viaducts;
a big fireball.
116
00:07:50,758 --> 00:07:53,241
When we got dispatched,
it was a rainy Sunday night.
117
00:07:55,620 --> 00:07:58,793
And ten he said
there's an airliner down,
and our mood just changed.
118
00:07:58,862 --> 00:08:02,172
And the one guy looked at me,
Dan, and said,
"Well, I hope it's a small one."
119
00:08:05,413 --> 00:08:08,517
When we pulled up,
120
00:08:08,586 --> 00:08:12,586
we saw the cockpit
and the word "West"
written on the fuselage.
121
00:08:12,655 --> 00:08:15,586
We looked at each other and
he said it looks like a big one.
122
00:08:16,241 --> 00:08:20,172
There's a trail
of scorched bodies and debris
more than a kilometre long.
123
00:08:23,482 --> 00:08:24,965
Just minutes after impact,
124
00:08:25,034 --> 00:08:28,620
paramedic Tim Schroeder
is on the scene,
looking for survivors.
125
00:08:29,482 --> 00:08:32,034
I'd never been to an accident
of that scale.
126
00:08:33,344 --> 00:08:36,931
We were struck
by the... the magnitude
of what we were seeing,
127
00:08:37,000 --> 00:08:38,793
the large scale of it.
128
00:08:38,862 --> 00:08:41,172
It was just...
it was almost overwhelming.
129
00:08:41,965 --> 00:08:45,000
From the little
that's left of Flight 255,
130
00:08:45,068 --> 00:08:48,034
it is unlikely
they'll find anyone alive.
131
00:08:49,000 --> 00:08:52,448
I buddied up with Dan
and we both started entering
the wreckage.
132
00:08:54,517 --> 00:08:59,517
It was probably a minute went by
and Dan actually heard, um,
a noise.
133
00:09:01,344 --> 00:09:05,068
He asked me a couple times,
you know, do I hear anything,
and I said no.
134
00:09:05,137 --> 00:09:07,103
And then finally I heard it.
135
00:09:07,172 --> 00:09:09,000
And there was more
like a faint cry.
136
00:09:11,379 --> 00:09:12,965
When I turned my head
to the right,
137
00:09:13,034 --> 00:09:15,724
I saw an arm...
underneath the seat.
138
00:09:16,517 --> 00:09:18,655
One, two, three, lift!
139
00:09:26,689 --> 00:09:29,896
She was covered in some blood
and some soot.
140
00:09:31,896 --> 00:09:36,000
Somehow,
four-year-old Cecilia Chican
has survived the crash.
141
00:09:37,862 --> 00:09:39,379
But she's badly injured.
142
00:09:40,931 --> 00:09:43,034
Tim Schroeder races her
to hospital.
143
00:09:43,103 --> 00:09:47,206
We have a four-year-old girl
found alive in the wreckage.
She has a very weak pulse.
144
00:09:47,275 --> 00:09:49,620
If Cecilia survived,
145
00:09:49,689 --> 00:09:51,965
perhaps others have, as well.
146
00:09:53,448 --> 00:09:57,068
Rescuers spend hours
looking through the wreckage
for more survivors.
147
00:09:58,068 --> 00:10:00,000
But their efforts
will be in vain.
148
00:10:01,241 --> 00:10:04,103
We actually covered
anything that...
149
00:10:04,172 --> 00:10:06,862
was a body or a body part
with a yellow blanket.
150
00:10:08,586 --> 00:10:12,206
It was just nothing but, like,
a sea of yellow blankets
basically.
151
00:10:13,758 --> 00:10:18,206
Northwest Airlines said
154 passengers and crew aboard
the plane died in the crash.
152
00:10:20,655 --> 00:10:24,379
Both Captain Maus
and First Officer Dodds
are killed in the crash.
153
00:10:24,448 --> 00:10:28,482
Two other people died
when their cars were hit
by the plane.
154
00:10:28,551 --> 00:10:32,620
This is the second-deadliest
airplane disaster
in U.S. history.
155
00:10:38,068 --> 00:10:41,034
Recovering in hospital
with serious head wounds
156
00:10:41,103 --> 00:10:43,310
is Flight 255's lone survivor,
157
00:10:43,379 --> 00:10:45,862
four-year-old Cecilia Chican.
158
00:10:45,931 --> 00:10:48,758
Despite her injuries,
doctors say she will live.
159
00:10:49,620 --> 00:10:52,068
Maybe, uh,
God was on her side that night.
160
00:10:55,137 --> 00:10:57,206
Within hours of the crash,
161
00:10:57,275 --> 00:10:59,137
Investigator Jack Drake
and his team
162
00:10:59,206 --> 00:11:01,586
from the National
Transportation Safety Board
163
00:11:01,655 --> 00:11:03,344
begin looking for clues.
164
00:11:04,965 --> 00:11:09,448
Drake is a former Navy pilot
who's been involved in hundreds
of crash investigations.
165
00:11:10,551 --> 00:11:12,379
You know
when you're at a crash site,
166
00:11:12,448 --> 00:11:16,068
because you get this combination
of burned plastic and kerosene,
167
00:11:16,137 --> 00:11:20,413
and sometimes combined
with fire-retardant foam
168
00:11:20,482 --> 00:11:23,034
that has
its own distinctive odour.
169
00:11:23,724 --> 00:11:25,931
You know you've arrived
when you smell it.
170
00:11:32,862 --> 00:11:36,517
Drake and his team
treat the crash site
like a crime scene.
171
00:11:37,620 --> 00:11:41,551
Our team consisted
of 12 or 13 specialists,
172
00:11:41,620 --> 00:11:45,206
some of whom go to the site
and some of whom
do their work elsewhere.
173
00:11:47,275 --> 00:11:50,103
They set out to examine
every piece of wreckage
174
00:11:50,172 --> 00:11:52,241
to discover what went wrong.
175
00:11:56,310 --> 00:11:59,448
They have responsibilities
for looking at different parts
176
00:11:59,517 --> 00:12:01,862
of the wreckage debris...
177
00:12:02,379 --> 00:12:04,896
...and do qualitative analysis
of those parts.
178
00:12:09,034 --> 00:12:10,965
We always look
for the recorders first.
179
00:12:11,034 --> 00:12:14,172
They're frequently referred
to as black boxes,
180
00:12:14,241 --> 00:12:15,931
although they're usually orange.
181
00:12:16,689 --> 00:12:19,275
The information
is usually well protected,
182
00:12:19,344 --> 00:12:22,344
because they're encased
in a steel box
183
00:12:22,413 --> 00:12:26,068
that is both heat-resistant
and crash-resistant.
184
00:12:28,206 --> 00:12:29,965
Since the 1960s,
185
00:12:30,034 --> 00:12:33,965
commercial jetliners have been
required to carry flight-data
and voice recorders.
186
00:12:34,931 --> 00:12:37,172
The CVR was first introduced
in Australia,
187
00:12:37,241 --> 00:12:41,000
following the 1960 crash
of a Fokker F27.
188
00:12:42,034 --> 00:12:46,482
The devices must be able
to withstand an impact
of 3,400 Gs
189
00:12:46,551 --> 00:12:50,206
and temperatures as high
as 1,100 degrees Celsius.
190
00:12:55,137 --> 00:12:57,413
The cockpit voice recorder
is intact.
191
00:12:58,758 --> 00:13:01,655
But the flight-data recorder
suffered some damage
in the crash.
192
00:13:04,724 --> 00:13:08,034
They may hold the only clues
that can help solve
this accident.
193
00:13:09,586 --> 00:13:13,793
Both recorders are sent
to the NTSB lab
in Washington, D.C.
194
00:13:19,827 --> 00:13:22,758
John Clark is Drake's
flight-performance engineer.
195
00:13:24,586 --> 00:13:29,206
His first task is to make
a map of the debris
left behind by Flight 255.
196
00:13:33,137 --> 00:13:35,482
When I first started
seeing the wreckage,
197
00:13:35,551 --> 00:13:39,758
it, uh... your mind immediately
starts turning to, uh...
198
00:13:39,827 --> 00:13:42,896
sorting out where it hit,
how it hit.
199
00:13:42,965 --> 00:13:44,655
Not where the wreckage ended up,
200
00:13:44,724 --> 00:13:48,310
but those first few inches
where the airplane
was coming down.
201
00:13:51,551 --> 00:13:55,448
Clark looks for ground scars
and other impact marks,
202
00:13:55,517 --> 00:14:00,103
and interviews witnesses
to piece together
where the plane fell and how.
203
00:14:01,379 --> 00:14:05,517
And, uh,
that kind of gives you
a sense of those last moments,
204
00:14:05,586 --> 00:14:07,655
what the airplane was doing
when it hit the ground.
205
00:14:09,310 --> 00:14:13,206
Clark begins to understand
the final moments of Flight 255.
206
00:14:14,517 --> 00:14:17,068
According to witnesses,
as it lifted off,
207
00:14:17,137 --> 00:14:20,310
it couldn't climb and flew
in a nose-high position.
208
00:14:22,620 --> 00:14:25,068
V1. Rotate.
209
00:14:25,896 --> 00:14:28,517
That could indicate
that the plane didn't have
210
00:14:28,586 --> 00:14:30,827
enough power
to get off the ground,
211
00:14:30,896 --> 00:14:32,931
that it didn't have
enough speed,
212
00:14:33,000 --> 00:14:36,344
or that high winds
prevented it from lifting off.
213
00:14:40,172 --> 00:14:42,793
Witnesses provide investigators
with a critical clue.
214
00:14:42,862 --> 00:14:44,448
You saw fire
coming from the engine?
215
00:14:45,344 --> 00:14:47,862
Several, including
an air-traffic controller,
216
00:14:47,931 --> 00:14:51,344
saw flames coming
from the plane's engine
before the crash.
217
00:14:52,379 --> 00:14:54,310
Damn!
No!
218
00:15:01,103 --> 00:15:04,068
The engines become
the first focus
of this investigation.
219
00:15:05,103 --> 00:15:08,068
They looked for evidence
of an internal failure.
220
00:15:08,137 --> 00:15:09,758
The plane suffered
an engine failure...
221
00:15:09,827 --> 00:15:13,034
Investigators soon learn
that less than a month earlier,
222
00:15:13,103 --> 00:15:16,965
one of the plane's engines
was damaged when it was hit
by a foreign object.
223
00:15:17,034 --> 00:15:21,068
It was repaired
and being monitored by mechanics
to see how it performed.
224
00:15:28,896 --> 00:15:32,827
The team studies the remains
of the engine for clues
that it had either caught fire
225
00:15:32,896 --> 00:15:35,068
or shut down on takeoff.
226
00:15:38,206 --> 00:15:40,413
Despite what the witnesses saw,
227
00:15:40,482 --> 00:15:43,620
they find no evidence of fire
or of a massive breakdown.
228
00:15:46,551 --> 00:15:50,413
The information suggested
that the engine operation
had been normal.
229
00:15:50,482 --> 00:15:52,310
Clamp, 100 knots.
230
00:15:55,310 --> 00:15:57,827
The flames were the result
of the fuel tank rupturing
231
00:15:57,896 --> 00:15:59,965
after the plane hit
a light pole.
232
00:16:02,896 --> 00:16:05,000
The fire didn't cause the crash.
233
00:16:06,896 --> 00:16:09,620
If Drake and his team
are to solve this mystery,
234
00:16:09,689 --> 00:16:11,758
they need to be certain
about what happened
235
00:16:11,827 --> 00:16:15,310
in the last few seconds
before Flight 255 crashed.
236
00:16:17,275 --> 00:16:19,689
Well, I think probably
the best physical evidence
237
00:16:19,758 --> 00:16:22,103
is what was
on the flight-data recorder.
238
00:16:22,172 --> 00:16:24,379
The flight-data recorder
doesn't tell you about weather,
239
00:16:24,448 --> 00:16:26,655
it tells you
about aircraft parameters,
240
00:16:26,724 --> 00:16:30,000
aircraft performance,
essentially, second by second,
241
00:16:30,068 --> 00:16:32,862
even at quarter-second intervals
in some parameters.
242
00:16:35,586 --> 00:16:37,482
But NTSB technicians
can't recover
243
00:16:37,551 --> 00:16:39,689
all the information
from the recorder.
244
00:16:41,448 --> 00:16:45,000
They send it to the manufacturer
to see if can recover
the lost data.
245
00:16:50,620 --> 00:16:53,689
While he waits for news
about the flight-data recorder,
246
00:16:53,758 --> 00:16:57,344
Jack Drake looks more closely
at the weather
on the night of the crash.
247
00:17:00,379 --> 00:17:04,896
There was some convective
or thunder-shower-type activity
that had moved through the area,
248
00:17:04,965 --> 00:17:08,344
and its impact on the accident
required a lot of analysis.
249
00:17:13,827 --> 00:17:17,103
Drake wonders how the storm
affected Flight 255.
250
00:17:17,931 --> 00:17:20,482
He listens to the cockpit
voice recorder for clues.
251
00:17:21,241 --> 00:17:24,689
He discovers
the menacing weather
was a concern to the crew.
252
00:17:26,241 --> 00:17:28,655
Let's get outta here
before it starts raining.
253
00:17:28,724 --> 00:17:30,862
Jesus, look at this.
254
00:17:32,448 --> 00:17:36,551
Drake sees
that there were several storms
along the flight path,
255
00:17:36,620 --> 00:17:38,448
and they were getting closer
to Detroit.
256
00:17:38,517 --> 00:17:40,241
There's a line here...
257
00:17:41,517 --> 00:17:43,551
...and a line between these two.
258
00:17:43,620 --> 00:17:45,034
Uh-huh.
259
00:17:45,103 --> 00:17:48,034
And another one here
about 25 miles wide.
260
00:17:50,137 --> 00:17:53,724
Thunderstorms can
create a very dangerous threat
to pilots.
261
00:17:55,517 --> 00:17:58,103
Since there was severe weather
in the area,
262
00:17:58,172 --> 00:18:00,551
we always worry
about microbursts.
263
00:18:02,896 --> 00:18:06,379
Microbursts occur
when columns of air
shoot down to earth.
264
00:18:07,413 --> 00:18:09,379
As a plane passes through,
265
00:18:09,448 --> 00:18:11,689
winds batter it
from all directions,
266
00:18:11,758 --> 00:18:13,517
making it difficult to control.
267
00:18:18,551 --> 00:18:20,551
In a microburst condition,
268
00:18:20,620 --> 00:18:22,931
you can get
very shifting winds,
and also vertical winds,
269
00:18:23,000 --> 00:18:25,586
that will try to push
the airplane into the ground.
270
00:18:25,655 --> 00:18:29,103
So you can get
a loss of airspeed,
a very rapid rise in airspeed,
271
00:18:29,172 --> 00:18:31,931
and then also actually push
the airplane toward the ground.
272
00:18:32,000 --> 00:18:35,241
And it requires
very aggressive flying
on the part of the flight crew.
273
00:18:36,379 --> 00:18:39,551
This unusual weather condition
had killed before.
274
00:18:40,965 --> 00:18:45,965
In 1985, a microburst
brought down a Delta Airlines
flight in Dallas,
275
00:18:46,034 --> 00:18:48,310
killing 137 people.
276
00:18:58,000 --> 00:18:59,896
At the time
of the Detroit accident,
277
00:18:59,965 --> 00:19:03,517
there was no device at airports
to accurately detect
microbursts.
278
00:19:04,344 --> 00:19:07,379
Instead, pilots relied
on reports from other crews.
279
00:19:12,482 --> 00:19:16,344
Jack Drake discovers
that 27 minutes before liftoff,
280
00:19:16,413 --> 00:19:19,896
Captain Maus
and First Officer Dodds
received such a warning.
281
00:19:21,517 --> 00:19:23,517
Ground, this is 722.
282
00:19:23,586 --> 00:19:26,413
You just had
a microburst out here.
The dust exploded down there.
283
00:19:29,551 --> 00:19:32,275
Investigators suspect that a microburst
284
00:19:32,344 --> 00:19:36,241
may have slammed Flight 255
to the ground
as it tried to lift off.
285
00:19:36,310 --> 00:19:39,724
It was right after departure
when the accident occurred.
286
00:19:39,793 --> 00:19:42,206
If they had struck
a very strong microburst,
287
00:19:42,275 --> 00:19:45,758
that would be a candidate
for one of the possible causes.
288
00:19:49,241 --> 00:19:52,655
Satellite images
taken at the time of the crash,
289
00:19:52,724 --> 00:19:54,517
and weather data
from the airport's sensors,
290
00:19:54,586 --> 00:19:58,310
show that there were storms
near the airport at the time
of the accident,
291
00:19:58,379 --> 00:20:00,551
but there's no evidence
of a microburst.
292
00:20:03,310 --> 00:20:05,827
Wind and rain, but nothing
that could be a microburst.
293
00:20:06,655 --> 00:20:08,586
Around the time of the crash,
294
00:20:08,655 --> 00:20:12,655
the airport's sensors did record
a dangerous gust of wind
on the runway,
295
00:20:12,724 --> 00:20:15,482
powerful enough to set off
alarms in the tower.
296
00:20:19,689 --> 00:20:21,965
Upon further investigation,
297
00:20:22,034 --> 00:20:26,344
Drake discovers that Flight 255
was still at the gate
at the time of that alarm.
298
00:20:26,413 --> 00:20:28,931
So the winds couldn't have
brought the plane down.
299
00:20:29,000 --> 00:20:31,034
Sign beacons.
300
00:20:31,103 --> 00:20:34,689
But they did have a huge effect
on Captain Maus's flight plan.
301
00:20:36,655 --> 00:20:38,931
The crew's pre-flight
dispatch package stated
302
00:20:39,000 --> 00:20:41,586
they would take off
from runway 21 Left.
303
00:20:44,758 --> 00:20:47,827
But with the sudden change
on wind direction,
304
00:20:47,896 --> 00:20:52,310
Ground Control sends Flight 255
to runway 3C,
305
00:20:52,379 --> 00:20:54,793
the shortest
of three available runways.
306
00:20:56,793 --> 00:20:59,965
Northwest 255,
now exit at Charlie,
runway 3 Centre.
307
00:21:05,931 --> 00:21:07,344
Yeah...
308
00:21:10,482 --> 00:21:13,137
Okay to Charlie for 3 Centre.
309
00:21:13,206 --> 00:21:15,275
Northwest 255.
310
00:21:15,344 --> 00:21:17,310
Charlie for 3 Centre, right.
311
00:21:17,379 --> 00:21:19,275
Okay.
312
00:21:20,344 --> 00:21:23,862
Controllers try to have planes
take off into the wind.
313
00:21:23,931 --> 00:21:27,517
The additional wind flowing
over a plane's wings
gives it more lift
314
00:21:27,586 --> 00:21:29,379
and helps it get off the ground.
315
00:21:30,275 --> 00:21:32,586
Taking off into the wind
is safer,
316
00:21:32,655 --> 00:21:35,000
but taking off
on the shorter runway
317
00:21:35,068 --> 00:21:39,241
now means First Officer Dodds
must recalculate
the plane's takeoff weight.
318
00:21:41,275 --> 00:21:42,931
If there's a runway change,
319
00:21:43,000 --> 00:21:47,034
you have to determine
if the weight of the aircraft
will permit it to accelerate
320
00:21:47,103 --> 00:21:49,241
and climb out safely;
and this varies,
321
00:21:49,310 --> 00:21:53,275
depending on the length
of the runway, temperature,
altitude of the airport.
322
00:21:53,344 --> 00:21:57,379
Perhaps First Officer Dodds made
a mistake in his calculation.
323
00:21:59,137 --> 00:22:02,931
4044?
How can we be that light
for a full airplane?
324
00:22:04,310 --> 00:22:05,862
If he did,
325
00:22:05,931 --> 00:22:09,275
it could explain why the MD-80
wasn't able to make it
off the ground.
326
00:22:10,482 --> 00:22:12,896
Runway 3C
simply wasn't long enough.
327
00:22:18,517 --> 00:22:23,344
Using calculations based
on average weight of luggage
and passengers on board,
328
00:22:23,413 --> 00:22:25,827
Drake's team confirmed
Dodds's estimate.
329
00:22:27,103 --> 00:22:31,068
The plane weighed
144,047 pounds,
330
00:22:31,137 --> 00:22:34,551
well below the allowable limit
for runway 3C.
331
00:22:34,620 --> 00:22:36,896
It should've been able
to get off the ground.
332
00:22:38,344 --> 00:22:41,620
Drake's investigation
has hit another dead end.
333
00:22:42,275 --> 00:22:44,793
He and his team are running out
of possibilities.
334
00:22:47,655 --> 00:22:50,931
Until technicians can decode
the damaged
flight-data recorder,
335
00:22:51,000 --> 00:22:53,827
the team must rely
on the physical evidence
336
00:22:53,896 --> 00:22:55,724
that's been found
at the crash site.
337
00:22:57,068 --> 00:23:00,000
But when investigators study
the cockpit's centre console,
338
00:23:00,068 --> 00:23:04,034
they're forced to consider
an almost unimaginable cause.
339
00:23:04,758 --> 00:23:06,344
Is this the way it was found?
340
00:23:08,724 --> 00:23:10,517
To get the plane
off the ground,
341
00:23:10,586 --> 00:23:14,379
the flaps on the wings
should've been extended
to the 11-degree position.
342
00:23:14,448 --> 00:23:17,793
But the way the flap handle
is damaged suggests
343
00:23:17,862 --> 00:23:20,206
the plane's flaps were retracted
when it crashed.
344
00:23:23,379 --> 00:23:25,586
The pin... had a left mark.
345
00:23:27,103 --> 00:23:30,482
This happens
because the aircraft
comes to a very sudden stop,
346
00:23:30,551 --> 00:23:33,206
and the handle jangles around
and...
347
00:23:33,275 --> 00:23:35,862
and it's a metal-to-metal
contact
348
00:23:35,931 --> 00:23:38,482
that's exaggerated
by the impact.
349
00:23:39,793 --> 00:23:41,827
It won't stay on.
350
00:23:43,965 --> 00:23:48,275
That indicator
was that the flaps were zero,
or fully retracted,
351
00:23:48,344 --> 00:23:50,068
and the slats were retracted,
as well.
352
00:23:52,275 --> 00:23:54,482
Flaps and slats are extensions
353
00:23:54,551 --> 00:23:57,551
that slide out of the back
and front of the wing.
354
00:23:57,620 --> 00:23:59,137
They make the wing bigger,
355
00:23:59,206 --> 00:24:01,896
which increases the amount
of lift they can provide.
356
00:24:01,965 --> 00:24:03,931
They must be extended
for takeoff.
357
00:24:06,689 --> 00:24:09,379
If the slats are retracted,
for the most part,
358
00:24:09,448 --> 00:24:13,206
with today's modern jets,
the airplane
is not capable of flight.
359
00:24:17,379 --> 00:24:20,689
If the crew tried to take off
with the flaps retracted,
360
00:24:20,758 --> 00:24:22,379
it would be
an astonishing blunder.
361
00:24:24,344 --> 00:24:26,068
V1. Rotate.
362
00:24:28,275 --> 00:24:32,689
But a pilot
who was lined up directly behind
Flight 255 on the runway
363
00:24:32,758 --> 00:24:35,068
is certain the plane's flaps
were extended.
364
00:24:35,137 --> 00:24:37,068
And you're sure
the flaps were extended?
365
00:24:38,931 --> 00:24:43,034
Pilots in other aircraft
that were close to the point
of where the takeoff had begun
366
00:24:43,103 --> 00:24:46,172
were telling us that
they thought the flaps and slats
367
00:24:46,241 --> 00:24:48,034
were deployed
to a normal position.
368
00:24:51,034 --> 00:24:54,620
Investigators can't be sure whether the flaps
were extended or not.
369
00:24:59,310 --> 00:25:04,000
The clues they need lie
somewhere in the sea of debris
recovered from the crash site.
370
00:25:08,000 --> 00:25:11,241
Eventually, investigators find
the evidence they need
371
00:25:11,310 --> 00:25:13,827
inside a section
of the plane's left wing.
372
00:25:15,068 --> 00:25:18,310
Each component
of the slat system
has its own drive system,
373
00:25:18,379 --> 00:25:20,000
and one of those was interrupted
374
00:25:20,068 --> 00:25:22,965
by the light pole
that passed through the wing.
375
00:25:23,034 --> 00:25:25,862
Eighteen feet of the left wing
was severed.
376
00:25:31,482 --> 00:25:34,206
The cable controlling the slats
was sliced in two
377
00:25:34,275 --> 00:25:35,896
when the wing hit
the light pole.
378
00:25:38,310 --> 00:25:40,793
Based on where the cable
was cut,
379
00:25:40,862 --> 00:25:45,862
investigators can tell
whether the slats and flaps
were extended or retracted.
380
00:25:54,034 --> 00:25:56,241
It severed two cables,
381
00:25:56,310 --> 00:25:58,931
and if you lined up
those two severed ends,
382
00:25:59,000 --> 00:26:03,931
it corresponded
with the slats being
in the full retracted position.
383
00:26:05,965 --> 00:26:08,000
It looks increasingly likely
384
00:26:08,068 --> 00:26:10,758
that the crew never extended
their flaps.
385
00:26:14,172 --> 00:26:17,137
Only the damaged flight-data
recorder can verify this.
386
00:26:22,758 --> 00:26:26,724
Fortunately,
technicians have finally been
able to rescue all its data...
387
00:26:28,724 --> 00:26:33,172
...a digital history
of Flight 255's performance
until the moment of impact.
388
00:26:35,586 --> 00:26:37,379
I knew that...
389
00:26:37,448 --> 00:26:40,689
if we had a good recorder,
we were gonna get data back.
390
00:26:40,758 --> 00:26:43,137
The flight-data recorders,
in combination,
391
00:26:43,206 --> 00:26:48,206
give you that time history
that goes together
with the physical evidence,
392
00:26:48,275 --> 00:26:50,206
or physical damage.
393
00:26:51,068 --> 00:26:52,586
As expected,
394
00:26:52,655 --> 00:26:56,172
the FDR confirms
what the evidence
has been showing investigators.
395
00:27:01,344 --> 00:27:04,103
The flight-data recorders
told us that the, uh,
396
00:27:04,172 --> 00:27:06,620
the flaps and slats
had not been extended.
397
00:27:11,275 --> 00:27:13,379
It's a major breakthrough.
398
00:27:13,448 --> 00:27:16,724
Drake now knows
what brought down Flight 255.
399
00:27:17,586 --> 00:27:21,172
But the flight-data recorder
doesn't answer
a more troubling question.
400
00:27:21,241 --> 00:27:23,586
So... why weren't
the flaps deployed?
401
00:27:24,275 --> 00:27:26,068
For some reason,
402
00:27:26,137 --> 00:27:29,551
a seasoned crew forgot one
of the most basic steps involved
403
00:27:29,620 --> 00:27:31,689
in getting an airplane
off the ground.
404
00:27:39,620 --> 00:27:41,482
Two months after the crash...
405
00:27:42,551 --> 00:27:45,793
...Northwest Airlines
Flight 255's sole survivor,
406
00:27:45,862 --> 00:27:48,965
Cecilia Chican,
is released from hospital.
407
00:27:49,034 --> 00:27:51,965
We can't be sure
why the little girl survived.
408
00:27:52,965 --> 00:27:56,758
She's a very little girl
buckled into a big seat.
409
00:27:56,827 --> 00:28:01,206
And she was more protected
than adults that might've been
sitting around her.
410
00:28:02,896 --> 00:28:04,517
So she was very lucky.
411
00:28:05,310 --> 00:28:07,931
Jack Drake needs to know
what contributed to the death
412
00:28:08,000 --> 00:28:10,068
of her family
and all the other victims.
413
00:28:13,413 --> 00:28:16,344
He finds an important clue
on the cockpit voice recorder.
414
00:28:17,862 --> 00:28:20,620
It shows that the last-minute
runway change
415
00:28:20,689 --> 00:28:22,689
caused confusion in the cockpit.
416
00:28:22,758 --> 00:28:25,517
Once the aircraft
began to taxi...
417
00:28:28,551 --> 00:28:31,758
- Blacker than hell out there.
- Northwest 255,
418
00:28:31,827 --> 00:28:34,586
now exit at Charlie,
runway 3 Centre.
419
00:28:35,344 --> 00:28:37,448
Other activities
were introduced
420
00:28:37,517 --> 00:28:40,551
that had the potential
to cause distractions.
421
00:28:41,793 --> 00:28:43,620
Did he say 3 Centre?
422
00:28:43,689 --> 00:28:47,000
3 Centre, yeah.
That's why I was thinking
we had to go that way.
423
00:28:47,068 --> 00:28:48,586
I was thinking 21.
424
00:28:49,482 --> 00:28:52,689
Well, they made a wrong turn,
which might've been confusing,
425
00:28:52,758 --> 00:28:54,896
because they had to go
a different route.
426
00:28:54,965 --> 00:28:56,482
Where's Charlie at?
427
00:29:00,000 --> 00:29:02,689
Right at the end of this ramp.
428
00:29:02,758 --> 00:29:04,827
- I think Charlie was--
- No, it is Charlie.
429
00:29:04,896 --> 00:29:06,172
You sure?
430
00:29:07,344 --> 00:29:08,793
I think so.
431
00:29:10,344 --> 00:29:13,379
The crew got lost
on the way to runway 3C.
432
00:29:13,448 --> 00:29:16,275
Ground, Northwest 255.
433
00:29:16,344 --> 00:29:20,379
I guess we went by Charlie.
We're going to 3 Centre, right.
434
00:29:20,448 --> 00:29:23,896
Northwest 255, affirmative,
make a left turn
at Foxtrot.
435
00:29:31,413 --> 00:29:34,827
They finally got to the runway
45 minutes late.
436
00:29:37,344 --> 00:29:40,137
Ladies and gentlemen,
we're currently number one
for departure.
437
00:29:40,206 --> 00:29:42,655
Should be rolling
in a couple of minutes.
438
00:29:42,724 --> 00:29:45,103
Flight attendants, be seated.
Thank you.
439
00:29:49,103 --> 00:29:53,241
Brakes.
But Jack Drake finds
something missing on the CVR.
440
00:29:54,620 --> 00:29:57,793
It seems the crew overlooked
a very important step.
441
00:29:58,413 --> 00:30:01,068
We're okay for the...
centre runway, aren't we?
442
00:30:03,793 --> 00:30:05,586
Before they got lost,
443
00:30:05,655 --> 00:30:09,172
the crew of Flight 255 performed
a number of checklists.
444
00:30:09,620 --> 00:30:12,758
But possibly due
to the confusion
of the runway change,
445
00:30:12,827 --> 00:30:16,206
they seemed to have completely
neglected the taxi checklist.
446
00:30:17,655 --> 00:30:20,275
They apparently
didn't consider the checklist,
447
00:30:20,344 --> 00:30:25,344
and key in the checklist
is the configuration
of the aircraft for departure.
448
00:30:26,000 --> 00:30:28,655
And the flight-data recorder
showed that was never done.
449
00:30:30,241 --> 00:30:33,137
There are hundreds
of small steps
for a crew to take
450
00:30:33,206 --> 00:30:35,241
to get a passenger jet
off the ground.
451
00:30:35,827 --> 00:30:37,896
Most of them are covered
by checklists.
452
00:30:39,793 --> 00:30:42,655
The checklist is a means
by which you ensure
453
00:30:42,724 --> 00:30:46,724
that important items
are positioned or done properly.
454
00:30:46,793 --> 00:30:50,103
- Transponder.
- Instead of doing it by memory,
455
00:30:50,172 --> 00:30:53,931
and having the possibility
of a lapse of memory...
456
00:30:55,034 --> 00:30:58,655
...flight crews use
a very rigorous
and regimented procedure
457
00:30:58,724 --> 00:31:00,275
of following the checklist...
458
00:31:00,344 --> 00:31:03,620
- Cabin-pressure control.
- ...to verify that each switch,
459
00:31:03,689 --> 00:31:05,931
each dial, each lever
is in the proper position
460
00:31:06,000 --> 00:31:08,000
before taking the runway
for departure.
461
00:31:09,689 --> 00:31:13,034
The first item
on the taxi checklist is flaps.
462
00:31:16,000 --> 00:31:18,758
One of the things
that would've been included
in their checklist
463
00:31:18,827 --> 00:31:22,034
was to configure the slats
and flaps for low-speed flight.
464
00:31:22,965 --> 00:31:25,206
But because they didn't run
the checklist,
465
00:31:25,275 --> 00:31:28,137
the crew never set their flaps
to the takeoff position.
466
00:31:28,206 --> 00:31:31,206
- I think Charlie was--
- No, it is Charlie.
467
00:31:31,275 --> 00:31:32,724
You sure?
468
00:31:34,379 --> 00:31:35,896
I think so.
469
00:31:37,103 --> 00:31:40,827
They hadn't done
this checklist at the time
they normally would.
470
00:31:40,896 --> 00:31:43,413
And as the activities piled up,
471
00:31:43,482 --> 00:31:45,655
um, that were potential
distractions,
472
00:31:45,724 --> 00:31:48,137
they were further
and further away from the point
473
00:31:48,206 --> 00:31:50,827
at which they would normally
perform that function.
474
00:31:50,896 --> 00:31:53,965
Their mindset was probably
that they had completed it.
475
00:31:57,034 --> 00:32:00,689
The pilots got
an indication that their plane
wasn't properly configured.
476
00:32:05,344 --> 00:32:08,068
During takeoff,
they couldn't activate
the autothrottle,
477
00:32:08,137 --> 00:32:10,655
because their computer
wasn't in takeoff mode.
478
00:32:11,068 --> 00:32:14,068
Another step covered
by the taxi checklist.
479
00:32:14,137 --> 00:32:15,896
It won't stay on.
480
00:32:17,241 --> 00:32:18,758
TCI is unset.
481
00:32:20,344 --> 00:32:21,931
This should've alerted them
482
00:32:22,000 --> 00:32:23,965
that they didn't perform
the checklist...
483
00:32:24,034 --> 00:32:25,896
If it had occurred to them
at that point
484
00:32:25,965 --> 00:32:29,620
that we might've missed
something else on the checklist,
485
00:32:29,689 --> 00:32:32,275
that could've led
to a rejected takeoff.
486
00:32:34,413 --> 00:32:36,551
They're on now.
487
00:32:38,034 --> 00:32:39,689
Hundred knots.
488
00:32:39,758 --> 00:32:41,586
Okay.
489
00:32:41,655 --> 00:32:43,724
Apparently,
that didn't happen,
490
00:32:43,793 --> 00:32:45,620
and so the takeoff
was continued.
491
00:32:46,344 --> 00:32:48,206
...with disastrous results.
492
00:32:58,241 --> 00:33:02,586
An alarm should've sounded
when the pilots tried to take
off with their flaps retracted.
493
00:33:02,655 --> 00:33:06,896
But for some reason,
investigators can't hear it
on the cockpit voice recorder.
494
00:33:09,275 --> 00:33:11,862
When it activates,
it alerts the crew
that the aircraft
495
00:33:11,931 --> 00:33:14,620
is not in a configuration
that's safe for takeoff.
496
00:33:16,206 --> 00:33:18,862
Maybe it went off
but we just can't hear it.
497
00:33:22,448 --> 00:33:25,034
The investigation team
is determined to find out
498
00:33:25,103 --> 00:33:27,000
why the takeoff warning
didn't sound.
499
00:33:27,793 --> 00:33:30,965
Technicians analyze
the cockpit voice recorder
for more clues.
500
00:33:32,310 --> 00:33:34,172
And they find something unusual.
501
00:33:37,482 --> 00:33:41,448
They picked up, uh,
some annunciations on the CVR
that were not correct.
502
00:33:41,517 --> 00:33:43,344
Stall.
503
00:33:44,586 --> 00:33:46,310
Stall.
504
00:33:46,379 --> 00:33:49,689
This warning
is alerting the crew that
the plane is about to stall.
505
00:33:50,724 --> 00:33:53,896
But it should be coming
from two speakers
in the cockpit.
506
00:33:53,965 --> 00:33:56,379
Stall.
507
00:33:56,448 --> 00:33:59,586
Technicians notice
it's only coming from one.
508
00:33:59,655 --> 00:34:01,551
Stall.
509
00:34:02,310 --> 00:34:03,827
Stall.
510
00:34:03,896 --> 00:34:06,793
As the airplane lifted off,
there was a stall warning,
511
00:34:06,862 --> 00:34:09,827
and it has
a typical characteristic
512
00:34:09,896 --> 00:34:12,551
of a sound like "stall-all,"
513
00:34:12,620 --> 00:34:14,379
because there are
two annunciations,
514
00:34:14,448 --> 00:34:17,000
and the purpose of that
is to provide redundancy.
515
00:34:17,068 --> 00:34:20,586
But that redundancy
wasn't there.
We had a single "stall."
516
00:34:22,896 --> 00:34:26,137
I went to an MD-80 sitting
on the ramp at Detroit.
517
00:34:28,137 --> 00:34:31,517
And a captain took us
through the process
of checking out
518
00:34:31,586 --> 00:34:34,206
to demonstrate
those different sounds.
519
00:34:34,275 --> 00:34:36,448
Let's start
with the config warning.
520
00:34:37,620 --> 00:34:40,655
The takeoff
configuration warning
is what would've alerted them
521
00:34:40,724 --> 00:34:42,344
about the flaps and slats.
522
00:34:42,413 --> 00:34:44,172
Flaps.
523
00:34:44,241 --> 00:34:46,241
Slats. Flaps.
524
00:34:47,724 --> 00:34:49,655
Can we get the stall warning
to sound?
525
00:34:51,275 --> 00:34:54,172
Stall all.
Stall all. Stall all.
526
00:34:54,241 --> 00:34:57,482
He activated
the stall-warning system
by a test switch,
527
00:34:57,551 --> 00:34:59,758
and it said: "Stall-all."
528
00:35:02,241 --> 00:35:05,172
The voice on the left channel
is slightly different
529
00:35:05,241 --> 00:35:07,793
from the voice on the right,
as it should be.
530
00:35:07,862 --> 00:35:11,758
But that's not what Clark heard
on Flight 255's voice recorder.
531
00:35:12,620 --> 00:35:14,275
Can you make it sound
like this?
532
00:35:15,379 --> 00:35:17,344
Stall.
533
00:35:17,413 --> 00:35:18,896
Stall.
534
00:35:18,965 --> 00:35:20,793
To get a singular stall,
535
00:35:20,862 --> 00:35:24,137
he had to pull power
to one side or the other.
536
00:35:24,206 --> 00:35:27,413
One way he demonstrated that
is he pulled
the P40 circuit breaker.
537
00:35:28,620 --> 00:35:30,896
A circuit breaker
is the electrical switch
538
00:35:30,965 --> 00:35:33,827
that protects the circuit
from damage caused by overload.
539
00:35:35,103 --> 00:35:38,655
The P40 circuit breaker
is an important one
in this investigation.
540
00:35:39,758 --> 00:35:44,241
It handled both
the failed takeoff-warning
and the stall-warning systems.
541
00:35:44,310 --> 00:35:48,103
What struck me was he said,
"I hear people doing it.
542
00:35:48,172 --> 00:35:51,413
I, of course,
don't do it myself,
but let me show you how."
543
00:35:51,482 --> 00:35:53,758
And he reached around
behind him,
544
00:35:53,827 --> 00:35:56,551
around behind the seat
and down low,
545
00:35:56,620 --> 00:35:59,620
and pulled the P40
circuit breaker without looking.
546
00:35:59,689 --> 00:36:03,482
And then, when he ran
the stall-warning system,
we got the singular "stall."
547
00:36:04,413 --> 00:36:06,275
Stall.
548
00:36:06,344 --> 00:36:08,172
Stall.
549
00:36:08,965 --> 00:36:10,758
It's a major clue.
550
00:36:11,413 --> 00:36:14,206
Clark could only reproduce
the strange-sounding
stall warning
551
00:36:14,275 --> 00:36:16,724
by pulling
the same circuit breaker
that's connected
552
00:36:16,793 --> 00:36:18,586
to the takeoff warning.
553
00:36:19,103 --> 00:36:21,689
This tells investigators
that the breaker was tripped
554
00:36:21,758 --> 00:36:24,000
when Flight 255 tried
to take off.
555
00:36:26,068 --> 00:36:30,000
Then John Clark notices
something else
about the P40 circuit breaker.
556
00:36:30,689 --> 00:36:33,275
You could see smudge marks
around the decals
557
00:36:33,344 --> 00:36:35,827
on each side
of the circuit breaker.
558
00:36:35,896 --> 00:36:38,206
It looked like fingermarks
where oil had built up,
559
00:36:38,275 --> 00:36:40,586
and dirt and grime,
over the years.
560
00:36:40,655 --> 00:36:42,862
So it told me
that circuit breaker
561
00:36:42,931 --> 00:36:45,689
was being used routinely
by a lot of pilots.
562
00:36:49,655 --> 00:36:51,448
Can you tell me
why that is so worn?
563
00:36:53,103 --> 00:36:56,103
It turned out
that the takeoff-configuration
warning
564
00:36:56,172 --> 00:36:57,724
could be a nuisance to pilots.
565
00:36:59,655 --> 00:37:01,379
If you're doing
a single-engine taxi,
566
00:37:01,448 --> 00:37:04,482
you have to push the throttle
up further to get a power
to taxi,
567
00:37:04,551 --> 00:37:07,068
and you would set off
the takeoff-warning system.
568
00:37:07,137 --> 00:37:09,586
So they would pull
the circuit breaker
to silence it.
569
00:37:14,000 --> 00:37:15,655
It's irritating.
It's a warning.
570
00:37:15,724 --> 00:37:17,862
It... it's meant to alert you.
571
00:37:17,931 --> 00:37:21,517
And if it's going off routinely
all the time,
572
00:37:21,586 --> 00:37:24,862
it gets on their nerves
and, uh...
573
00:37:24,931 --> 00:37:30,655
so... apparently pilots
were routinely silencing
those takeoff warnings.
574
00:37:34,551 --> 00:37:38,724
Investigators suspect
that the crew of Flight 255
575
00:37:38,793 --> 00:37:41,724
tripped the breaker to avoid
the irritating takeoff warning.
576
00:37:43,206 --> 00:37:46,965
And then, with the added delay
from the runway change
and the impending storm...
577
00:37:48,275 --> 00:37:51,758
...they proceeded to take off
without doing
the taxi checklist.
578
00:37:54,137 --> 00:37:56,586
That might explain
why the alarm didn't sound
579
00:37:56,655 --> 00:37:59,862
when they tried to take off
with their flaps retracted.
580
00:37:59,931 --> 00:38:04,241
We don't know if the pilot
did pull that circuit breaker
on that particular flight.
581
00:38:04,310 --> 00:38:08,172
There was certainly one error
and the potential for two.
582
00:38:08,241 --> 00:38:10,551
I think the extensive use
of the circuit breaker,
583
00:38:10,620 --> 00:38:13,793
because of the smudge marks
around the circuit breaker
and the pilots' statements,
584
00:38:13,862 --> 00:38:15,827
I think it's highly likely
that he did.
585
00:38:20,137 --> 00:38:24,862
It appears
the downing of Flight 255
was caused by pilot error.
586
00:38:29,275 --> 00:38:32,206
Now investigators
can accurately piece together
587
00:38:32,275 --> 00:38:34,000
what happened that night
in Detroit.
588
00:38:36,034 --> 00:38:38,137
But it would take another
shocking accident
589
00:38:38,206 --> 00:38:40,793
for the airline industry
to learn its lesson.
590
00:38:47,379 --> 00:38:51,862
Jack Drake's team
has discovered what caused
the crash of Flight 255...
591
00:38:53,000 --> 00:38:55,172
...but cannot prevent it
from happening again.
592
00:38:56,000 --> 00:38:58,206
One year later, in Dallas,
593
00:38:58,275 --> 00:39:02,689
Delta Flight 1141
tried to take off
without their flaps extended.
594
00:39:04,551 --> 00:39:08,344
The investigators
who had been working on
the Northwest crash are stunned.
595
00:39:09,344 --> 00:39:11,724
I was very frustrated
to learn that...
596
00:39:11,793 --> 00:39:14,620
that another airline
had done the same thing
597
00:39:14,689 --> 00:39:17,068
in a different aircraft type
about a year later.
598
00:39:17,137 --> 00:39:20,896
The Delta crash would uncover
potentially deadly flaws...
599
00:39:20,965 --> 00:39:23,344
Okay, Before Start checklist,
battery. Uh...
600
00:39:23,413 --> 00:39:25,827
...in the checklists
commercial pilots are trained
to follow.
601
00:39:30,551 --> 00:39:34,310
The Delta and Northwest crashes
killed 170 people...
602
00:39:35,482 --> 00:39:37,862
...and had
eerily similar causes.
603
00:39:38,758 --> 00:39:42,310
In both disasters, the workload
in the cockpit increased...
604
00:39:42,379 --> 00:39:44,793
Jesus... look at this.
605
00:39:44,862 --> 00:39:46,344
Northwest 255,
606
00:39:46,413 --> 00:39:48,206
now exit at Charlie, runway 3...
607
00:39:48,275 --> 00:39:51,103
If we get outta here
pretty quickly,
we won't have a delay.
608
00:39:51,172 --> 00:39:53,000
And in both,
609
00:39:53,068 --> 00:39:55,896
the pilots failed to perform
vital elements
of their checklists.
610
00:39:58,862 --> 00:40:01,620
It is very unusual for a crew
to not perform a checklist.
611
00:40:01,689 --> 00:40:04,344
They have done it hundreds
upon hundreds of times.
612
00:40:04,413 --> 00:40:06,206
Brakes.
613
00:40:06,275 --> 00:40:08,862
Windshield heat... is on.
614
00:40:08,931 --> 00:40:11,655
Cabin-pressure controller...
is checked.
615
00:40:11,724 --> 00:40:16,000
The normal procedures, uh,
were a little bit
out of the norm.
616
00:40:16,068 --> 00:40:18,034
And as a result,
it got overlooked.
617
00:40:19,379 --> 00:40:21,862
To prevent this
from happening again,
618
00:40:21,931 --> 00:40:24,172
aviation officials turned
to a government agency
619
00:40:24,241 --> 00:40:26,517
that knows the importance
of clear procedures:
620
00:40:27,724 --> 00:40:30,586
- Four, three, two...
- Discovery, you're go.
621
00:40:30,655 --> 00:40:32,172
...one.
622
00:40:34,137 --> 00:40:35,655
...NASA.
623
00:40:37,448 --> 00:40:40,344
- So they're ready to go.
- Alright.
624
00:40:40,413 --> 00:40:43,344
Jack Drake and his team wanted
the U.S. space agency
625
00:40:43,413 --> 00:40:47,310
to help create checklists
that decrease the odds
of items being skipped.
626
00:40:48,448 --> 00:40:52,103
Asaf Degani
was a research scientist
working with NASA.
627
00:40:54,275 --> 00:40:56,034
After the accident,
628
00:40:56,103 --> 00:40:59,620
he took on the project
of improving a flight crew's
pre-takeoff procedure.
629
00:41:00,137 --> 00:41:04,448
We looked for any research
that was done on checklists
or procedures in general.
630
00:41:04,931 --> 00:41:06,793
And, in fact,
we couldn't find anything.
631
00:41:09,206 --> 00:41:11,482
So Degani
had to start from scratch.
632
00:41:12,551 --> 00:41:15,275
But there are dozens
of different checklists
to examine.
633
00:41:18,482 --> 00:41:22,310
Most of the ones on Flight 255
were printed on a single card.
634
00:41:24,241 --> 00:41:27,344
They listed the tasks
the crew had to carry out,
635
00:41:27,413 --> 00:41:31,379
but didn't give them
a way to keep track
of what and what wasn't done.
636
00:41:32,862 --> 00:41:35,448
At the time
of the Northwest crash,
637
00:41:35,517 --> 00:41:38,724
there were several types
of mechanical checklists in use.
638
00:41:38,793 --> 00:41:41,931
The U.S. Air Force used
a scrolling checklist.
639
00:41:42,000 --> 00:41:43,931
Once a checklist item
is completed,
640
00:41:44,000 --> 00:41:46,034
the pilot scrolls
to the next one.
641
00:41:47,241 --> 00:41:49,793
American Airlines used a system
that allowed pilots
642
00:41:49,862 --> 00:41:53,172
to cover up completed items
with a plastic slide,
643
00:41:53,241 --> 00:41:56,310
so only the non-completed items
would be displayed.
644
00:42:00,379 --> 00:42:04,931
Asaf Degani set out
to see firsthand how pilots
were using checklists.
645
00:42:05,931 --> 00:42:08,827
He wanted to make it less likely
for them to make mistakes.
646
00:42:11,551 --> 00:42:15,206
He sat in cockpits and observed
42 different crews in action.
647
00:42:16,586 --> 00:42:20,068
Degani concluded
that many checklists
were badly designed.
648
00:42:21,896 --> 00:42:25,758
There's a certain flow
by which you go about
checking things.
649
00:42:25,827 --> 00:42:29,896
And the idea is to prevent
the case where you're doing
one thing here, one thing there.
650
00:42:31,896 --> 00:42:33,689
A checklist should have
a certain flow,
651
00:42:33,758 --> 00:42:37,310
which is a logical flow and not
one which is kind of random.
652
00:42:38,137 --> 00:42:40,758
And they're ready
and they're going through...
653
00:42:40,827 --> 00:42:44,379
Degani also found
a much more serious problem
with checklists.
654
00:42:45,620 --> 00:42:49,068
If pilots are interrupted,
they sometimes forget
where they left off.
655
00:42:49,137 --> 00:42:51,068
Transponder...
656
00:42:51,137 --> 00:42:52,689
checked and on.
657
00:42:52,758 --> 00:42:57,172
And there's many cases
where people would do, A, B,
C, D, E,
658
00:42:57,241 --> 00:43:01,068
an Air Traffic call would come,
they'd have to respond to it,
and that's an interrupt.
659
00:43:01,965 --> 00:43:05,689
Northwest 255,
now exit at Charlie,
runway 3 Centre.
660
00:43:05,758 --> 00:43:07,310
Yeah...
661
00:43:07,379 --> 00:43:09,517
They would go back
to the checklist,
662
00:43:09,586 --> 00:43:12,551
and skip a certain item
and continue on the list,
663
00:43:12,620 --> 00:43:14,758
assuming that the whole list
was done.
664
00:43:14,827 --> 00:43:17,206
People were very concerned
about that.
665
00:43:19,034 --> 00:43:21,379
To ensure no steps are missed,
666
00:43:21,448 --> 00:43:24,620
airlines train their pilots
to return to the top
of a checklist
667
00:43:24,689 --> 00:43:26,896
following the interruption
and start over.
668
00:43:27,965 --> 00:43:30,241
Again, Asaf Degani
sees a problem.
669
00:43:33,586 --> 00:43:37,206
And we found
that if checklists are very,
very long and meticulous, um,
670
00:43:37,275 --> 00:43:39,965
that's overburdening the crew
and they sometime would not want
671
00:43:40,034 --> 00:43:42,000
to start again
from the beginning.
672
00:43:43,275 --> 00:43:44,758
To address the problem,
673
00:43:44,827 --> 00:43:48,000
Degani suggests changes
across the airline industry.
674
00:43:52,103 --> 00:43:54,034
One of our recommendations
from the study
675
00:43:54,103 --> 00:43:58,137
is to try to take
long checklists
and chunk them to small pieces,
676
00:43:58,206 --> 00:44:00,137
so that if an interruption
happens,
677
00:44:00,206 --> 00:44:02,965
then doing another
four or five items,
678
00:44:03,034 --> 00:44:06,034
it's not a big effort,
as opposed to doing 20.
679
00:44:06,965 --> 00:44:08,793
Degani even made recommendations
680
00:44:08,862 --> 00:44:11,103
about the typeface
that airlines use
681
00:44:11,172 --> 00:44:13,931
so they can be more easily read
by pilots.
682
00:44:15,896 --> 00:44:20,241
Perhaps the biggest advance
to checklists is the move
from paper to computers.
683
00:44:20,310 --> 00:44:24,379
Since, at the time, um,
computer technology was coming
into the cockpit,
684
00:44:24,448 --> 00:44:28,620
it made a lot of sense to think
about electronic checklists.
685
00:44:29,758 --> 00:44:33,068
Today, Degani and his team
are studying smart checklists
686
00:44:33,137 --> 00:44:35,517
that keep track
of checked items.
687
00:44:35,586 --> 00:44:40,068
They provide pilots
with a visual indication
of where they are on the list,
688
00:44:40,137 --> 00:44:43,655
and in some cases,
verify that the task has been
correctly carried out.
689
00:44:45,000 --> 00:44:47,482
An electronic checklist
shows you which item...
690
00:44:47,551 --> 00:44:49,827
was completed
and which item was not.
691
00:44:54,206 --> 00:44:57,448
Computerized checklists
are now slowly making their way
692
00:44:57,517 --> 00:44:59,379
into the cockpits
of commercial airplanes.
693
00:45:00,448 --> 00:45:04,413
They make it far less likely
that an accident
like Northwest 255
694
00:45:04,482 --> 00:45:06,413
could happen again.
695
00:45:08,620 --> 00:45:11,172
The FAA also ordered
a modification
to the alarm system
696
00:45:11,241 --> 00:45:14,172
of all commercial jetliners
to prevent nuisance alarms.
697
00:45:15,344 --> 00:45:17,310
The takeoff warning
was redesigned
698
00:45:17,379 --> 00:45:20,482
so it could not sound
unless the plane
was actually taking off.
699
00:45:25,034 --> 00:45:28,000
Jack Drake went on
to investigate hundreds
of accidents
700
00:45:28,068 --> 00:45:31,275
over a 26-year career
with the NTSB.
701
00:45:32,000 --> 00:45:35,241
The crash of Flight 255
taught him a valuable lesson.
702
00:45:37,758 --> 00:45:40,724
This one
is a worldwide example of...
703
00:45:40,793 --> 00:45:42,862
the importance
of following checklists
704
00:45:42,931 --> 00:45:47,275
and configuration
being completed correctly
on every takeoff.
705
00:45:48,172 --> 00:45:51,448
And so it became something
that was a part
of the training curriculum
706
00:45:51,517 --> 00:45:53,310
in virtually every airline
around the world.
707
00:45:53,379 --> 00:45:55,793
The case of Northwest 255
is no different.
708
00:45:55,862 --> 00:45:57,620
It was a series of events:
709
00:45:57,689 --> 00:46:01,379
runway change, task saturation,
an overlooked checklist,
710
00:46:01,448 --> 00:46:04,517
a failed takeoff warning system.
711
00:46:04,586 --> 00:46:07,448
Put all of those together,
those links in a chain,
712
00:46:07,517 --> 00:46:09,241
and you end up
with the accident.
713
00:46:09,310 --> 00:46:12,310
If you were to break
any one of those links,
714
00:46:12,379 --> 00:46:13,931
the accident
wouldn't have happened.
715
00:46:16,551 --> 00:46:20,413
Flight 255
will also be remembered
for its lone survivor,
716
00:46:20,482 --> 00:46:22,137
Cecilia Chican.
717
00:46:22,896 --> 00:46:25,896
She's never spoken publicly
about the death of her family.
718
00:46:28,551 --> 00:46:31,896
But she's stayed in touch
with the people
who rescued her that day.
719
00:46:33,689 --> 00:46:36,689
She's full of life,
and the conversations we have,
720
00:46:36,758 --> 00:46:40,896
it's more about, you know,
her sports and her husband
and her vacations.
721
00:46:40,965 --> 00:46:42,586
She just said maybe one day,
722
00:46:42,655 --> 00:46:45,931
she'll come out and tell
the world what Cecilia is doing.
723
00:47:00,000 --> 00:47:02,068
difuze